During the night two of my chromis found there way into the corner overflow chamber of my tank ! The flow and return pipework is glued into place so I can't remove it which makes getting a net in **** near impossible ! After a lot of head scratching I decided to slowly fill the overflow with substrate in order to force the two fish upwards ! This method worked fine and the two adventurers are now back in the DT with the rest of the mob ! My problem now is the overflow is now half full of crushed coral sand/gravel ! My question is "should I try to remove this or if I leave it will it act as a DSB ? any advice would be much appreciated !!!

Thanks mate ! I'm having mixed thoughts !!! If I leave it I'm hoping it will act as a dsb and a breeding ground for pods for my mandarin and also easier to retrieve any fish that go in there ! But on the down side I'm thinking about the phosphate pockets and all out nitrate factory it will eventually become !!! The system has always been fine so I think I'll remove it and put it back to how it's always been ! If it's not broke don't try to fix it etc etc

I have had the same problem in the past. I do not glue the stand pipe into the bulkhead adapter so I can remove it and get into the overflow if needed and it gives me more room to get a net/hand in. I know that doesn't help you now but just thought I'd mention it.

The stand pipe was already glued when I got this tank or I could have put the net over the end in my sump and just pulled the pipe and caught the little fellas lol ! Think I'm gonna take this gravel out though !